Merge pull request #2041 from To1ne/tc-gitbutler

guis: add GitButler

Author: dscho

data/guis/gitbutler.yml

@@ -0,0 +1,12 @@
+---
+name: "GitButler"
+project_url: "https://gitbutler.com"
+image_tag: "images/guis/gitbutler.png"
+platforms:
+  - "Mac"
+  - "Linux"
+  - "Windows"
+price: "Free"
+license: "FSL-1.1-MIT"
+order: 21
+---